But now, the group finds itself fighting off an effort by conservative organizations that are trying to get corporations to yank their sponsorships because the Big Brothers Big Sisters has mandated that its chapters welcome gay and lesbian volunteers as part of its nondiscrimination policy.

According to its Web site, Big Brothers Big Sisters, which was founded in 1904, "provides one-to-one mentoring relationships between adult volunteers and children primarily from single-parent families in over 500 programs throughout the United States."

The Colorado-based religious group Focus on the Family has called for a boycott of the Big Brothers Big Sisters organization, which is based in Philadelphia, after it issued a new version of its "standards and practices" policy last month that requires all 490 chapters to accept gays and lesbians as volunteers. Previously, chapters had been able to develop their own guidelines while using the national policy as a model.

"This policy is a brazen affront to parents with deeply held religious beliefs, not to mention a potential hazard to the well-being of children everywhere," said Bill Maier, vice president and psychologist-in-residence for Focus on the Family.

The group, previously a supporter of Big Brothers Big Sisters , yanked its endorsements of the mentor organization and initiated a mass e-mail campaign among its membership to get members to write to the group's corporate sponsors.

Donald Wildmon, chairman of the American Family Association in Tupelo, Miss. , contends that Big Brothers Big Sisters "will become a magnet for homosexuals who exploit opportunities to engage young, impressionable children with their unhealthy lifestyle."

His association's Web site offers a form letter to be sent to Big Brothers Big Sisters' corporate supporters, asking that they suspend donations until the group "repeals this dangerous and troubling policy."

The boycott effort has not resulted in any corporate funding withdrawals, said Big Brothers Big Sisters spokeswoman Noreen Shanfelter, but said it was not clear how or whether individual donations were impacted.

"I feel pretty safe to say there have been no corporate donations lost," Shanfelter said.

Larry Plumb, a spokesman for Verizon Communications, said his company had a long track record in support of nondiscrimination and would not withdraw its sponsorship. Martin Kish, vice president of communications for Valvoline, said his company was studying the Big Brothers Big Sisters' policy -- but so far remained steadfast in its support.

Shanfelter said Focus on the Family was trying to stir up controversy by claiming that the group was "forcing agencies to match active homosexuals with children."

Of the 490 chapters within the organization, only four or five have complained about the mandate and most already have been accepting gay and lesbian volunteers, Shanfelter said.